Coats Disease

Overview

Coats disease is a rare eye condition that affects the blood vessels in the retina. The retina is the light-sensitive layer at the back of the eye. In Coats disease, some blood vessels become abnormal and leak fluid or blood. This can damage the retina and cause vision loss. It is not cancer, not an infection, and not contagious. It usually affects one eye.

Coats disease is rare. Only a small number of people are diagnosed with it each year.

It mostly affects children, and it is more common in boys. It usually affects one eye. A rare adult form can also occur. Coats disease is not caused by anything a parent did.

Symptoms

Common symptoms

• Blurred or reduced vision in one eye
• An eye that turns in or out, called a squint
• A white or cloudy reflection in the pupil, sometimes seen in photos
• Redness or pain if pressure inside the eye rises
• Floaters or flashes if the retina is affected

Symptoms in children

• A parent may notice a white pupil in a photo
• One eye may turn in or out
• A child may not see well in one eye
• A child may hold things close or cover one eye
• Sometimes there are no obvious symptoms until vision is already affected

Symptoms in older adults

• Coats disease is much less common in older adults.
• Adult-onset cases can cause blurred vision, floaters, or vision loss.
• Eye pain or redness can happen if complications develop.

Causes

Main causes

• The main cause is abnormal development of blood vessels in the retina.
• These abnormal vessels leak fluid and blood, which can damage the retina.
• Coats disease is not cancer, not an infection, and not contagious.

Risk factors

• Being a boy
• Being a child, especially in early childhood
• A rare adult-onset form exists, but it is uncommon
• A family history is uncommon, but it may be possible in rare cases

When to see a doctor

See a doctor urgently if:

• A new white reflection in a child's pupil
• A new eye turn or squint
• Vision that gets worse quickly
• Eye pain, redness, or swelling that does not settle

Book a routine appointment if:

• You or your child has a lazy eye or a change in glasses prescription
• You have a family history of a rare eye condition
• You have Coats disease and need a routine follow-up
• A child has a routine vision check at school or with a doctor

Diagnosis

An eye doctor can check for Coats disease by looking inside the eye. They use eye drops to widen the pupil so they can see the retina clearly. They may also use special cameras or scans to look at the blood vessels and the back of the eye.

Tests that may be done

• Dilated eye exam: eye drops widen the pupil so the retina can be seen
• Eye ultrasound: sound waves make a picture of the eye
• Fluorescein angiography: a dye and special camera show the blood vessels
• Optical coherence tomography (OCT): light waves make detailed pictures of the retina
• Eye pressure check

What to expect at your appointment

The eye exam is usually painless, but the drops may sting briefly and blur vision for a few hours. Your child may need to be seen by a children's eye specialist. Some tests may need follow-up visits.

Treatment

The goal is to find and treat leaky blood vessels before they damage the retina. Treatment also aims to manage problems like retinal detachment or high eye pressure. An eye specialist will plan the best approach.

Self-care at home

• Go to all eye appointments, even if vision seems stable
• Tell your eye doctor about any new flashes, floaters, or vision changes
• Use glasses or low-vision aids as advised
• Protect the healthy eye with safety glasses during sport or DIY
• If your child has patching or other therapy, follow the eye team's instructions

Medical treatments

Eye doctors may use laser treatment to seal leaking vessels. They may use freezing treatment for areas that laser cannot reach. They may also give injections into the eye of medicines that reduce leakage and abnormal vessel growth. They may treat high eye pressure or a detached retina. These treatments are chosen by your eye specialist.

When is surgery considered?

Surgery may be needed if the retina detaches, if bleeding inside the eye does not clear, or if eye pressure cannot be controlled. An eye surgeon will explain the risks and benefits.

Living with this condition

Living with Coats disease usually means regular eye check-ups and watching for changes. Children may need visits with a children's eye team and support at school. Many people use glasses, low-vision aids, or other help to make the most of their vision.

Lifestyle tips

• Wear safety glasses for sport, DIY, or other risks to the eye
• Keep up general health checks and a healthy lifestyle
• Do not smoke, and avoid second-hand smoke
• Ask about low-vision support at school or work
• Use good lighting and magnifiers if they help

Diet and exercise

There is no special diet for Coats disease. Regular activity and a balanced diet support general health. Protect your eyes during exercise or contact sports.

Mental health and emotional wellbeing

A rare eye condition can feel worrying for parents and children. It is normal to feel anxious or sad. Talk to your eye team, school, or a counselor. If you or your child feel overwhelmed, contact your local mental health service or crisis line. If there is immediate danger, call your local emergency number.

Prevention

There is no known way to prevent Coats disease. It is not caused by diet, screen time, or anything a parent did.

Vaccines

There is no vaccine for Coats disease.

Screening programmes

There is no special screening programme for Coats disease. Children's vision checks and a prompt eye exam for a white pupil or new squint are important. If there is a family history of rare eye disease, ask your eye doctor whether extra checks are needed.

Complications

If left untreated

• Vision loss in the affected eye
• Retinal detachment: the retina pulls away from the back of the eye
• Glaucoma: high pressure inside the eye that can damage sight
• Cataract: clouding of the lens
• Eye pain, redness, or a shrinking eye in advanced cases

Long-term outlook

Many people with Coats disease can keep useful vision, especially when it is found and treated early. Some will have permanent vision loss in the affected eye. Regular eye care and support can help you make the most of your sight.

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